Just replaced my gaskets and redid the silicone on my intake manifold due to a decent oil leak from the previous owner, that made me think the rear main may be leaking. It looks like this fixed my oil leak issues, but since we put the intake back on there has been a horrible stumble. The needle just bounces around 5-600 rpms and sounds like its gonna die(and rattles the dash nicely). We checked all over for an open vaccum line or leak anywhere, cause the symptoms definately point that way, but we can't find a thing. My dad thinks we fixed the vaccum leak that was there, and now the IAC just hasn't reset yet or something... But Ive put like over 30 mi on it since then, and the only change is that at first any time you werent on the gas it would stumble @ 600, but now it only does it when you come up to a light or while your driving down the road w/ no load on it... Its not doing it now, when you start the car and just let it sit and idle, like it was right after we fixed the leak.. Please Help!! And thanks....



Nick

 

sounds like you mixed up one of your injector wires, the injectors are labeled 1-8 id check them all.

 

We've been all over this thing. Nothing that simple got by us.. The Injectors are all connected correctly, cant find any open vaccum source, or unplugged wire.. What could this darn thing be??

 

I have the same problem. Acted like a lazy IAC. It would stumble real bad coming off the gas, like up to a light. Sometimes it would even stall. If i feathered the throttle, it would stay running, and then I could hear a rush if air being let into the engine from the air filter. It would then idle fine until i drove the car and came back to a light. I replaced the Iac and it still does it.

If you find anything , let me know.

 

Bad sensor: ` engine temp,O2, MAF, etc
Elbow has a tear or small leak ~ check by listening or vacuum guage
Electrical leak in opti or wires-especially coil wire
clogged injector

 

Well, the IAC was pretty carboned up for a 400 mi motor, must have been reused... But cleaning it didn't fix it, so we just adjusted the manual idle control on my AS&M TB up to around 1000 rpms, where it was idling, and it seems fine now. My old man thinks the OBD 1 are so slow reseting, and it being stuck is what caused it... But IDK.. Im waiting on a laptop to run my LT1 edit on my pcm to check the current settings for idle, iac, etc. I just hope it stays as it is.. And we didn't somehow just manually over ride the problem, but oh well..



Thanks a lot guys!



Hope you guys aren't fixing as many of other peoples screw ups as I am...

 

When you pulled the manifold, did you pull the fuel rails and injectors out first? And chance you lost or damaged the injector O-rings?